burn away the chill
by bravevulnerability
Summary: 'He was simply a last resort, someone to brainstorm with. That was all.' Beckett stops by the loft seeking Castle's thoughts on their case. Set in the middle of 1x05.
1. Chapter 1

_**A/N: **__**Set during 1x05 (A Chill Goes Through Her Veins).**_

_**This turned out a lot differently than the original idea in my head. Not sure if that's a good thing or not.**_

* * *

She had spent her entire evening at the precinct, stalking back and forth in front of the murder board, scrutinizing the daunting pictures and her own neat, handwritten notes beside them, willing the answer to come, for Sam to tell her _how _he had killed his wife. But the truth only continued to elude her and further her frustration.

Something wasn't right in the Cavanaugh case and it was gnawing at her like an itch she was unable to scratch. The people involved - the victim's family - deserved to know the whole story. Not a theory they _thought _to be true. It wasn't enough for them, and it wasn't enough for her.

And that was why Detective Beckett had ended up at his building, greeting his doorman with a forced smile and quietly cursing to herself during the smooth ride up the classy elevator to his floor. He was simply a last resort, someone to brainstorm with. That was all.

After being let in to what seemed like a madhouse – a gorgeous madhouse that had her eyes widening as they scanned the spacious vicinity of his loft when his back was turned – by Castle and his daughter, both glowing blue and green in what looked to be some kind of laser tag gear, and his effervescent mother with her welcoming, white smile standing out against the mint green of her facial mask, Castle led her into his office.

She made a comment, comparing the room to the Batcave, and he'd equated her to the famous comic book character, pointing out the similarities.

_Loss of a loved one leads to a life of fighting crime._

She had taken a moment to examine the Nikki Heat murder board he had created, noting the similarities to the one she used at the precinct, and then he'd asked her what was wrong, his voice heavy with curiosity. She didn't fault him for that; she had been the one to show up uninvited at his home without stating her reason for being there.

"I can't find it." she said, gritting her teeth and keeping her back to him, feeling the thick tendrils of failure twisting around her insides like barbed wire.

"Find what?"

"The answer." she replied, turning back around and letting her hands drop tiredly to hang at her sides.

The curiously puzzled expression blossomed over his features as he studied her for a moment and she found herself absently admiring how attractive he looked that night, dressed down in a soft, burgundy sweatshirt with black sleeves and a worn pair of jeans that hugged him nicely. So different from how he usually dressed at the precinct.

She liked seeing him at home.

"It was Sam," he assured her. "Everything fits, it's a good ending."

"Yeah, but without proof it's just a _theory._ And that family, those kids, they need more than just a theory. They need to know, _I _need to know." she insisted vehemently, a little too much urgency in her tone. And she knew she had revealed too much, had made a mistake coming here, by the way he looked at her.

His eyes darted to the watch on her wrist, her father's watch. He'd made a quip about it in the car the day before, thinking he had her story somewhat figured out, believing it was her father she had lost. Her cellphone had interrupted her chance at answering him then, interrupted her chance at correcting him.

She sighed and scraped a hand through her short hair. "It was my mother. Not my father."

It sent a strange rush through her bones to see the light change so quickly in his eyes, flashing an electric blue in the dim glow of lamplight his office provided, so thirsty for her story. But the rest of his body remained the same - posture open as he watched her from a chair beside his desk, head tilted slightly to indicate he was listening. And before she could stop it, the words were spilling out, the story he'd so desperately sought tumbling into the space between them.

"We were supposed to go to dinner, my mom, my dad, and I…"

His eyes dimmed as she spoke, growing dark and losing the flare of childlike curiosity that had shone so brightly just seconds before, turning almost the color of storm clouds as she revealed the tragedy that had claimed her life ten years ago. She could already see the story playing out before him through her recounting of the homicide case she knew all too well, as if he had been right there with her to witness the scene himself.

When she uttered what was probably the hardest sentence, that her mother had been stabbed, Kate noticed how his body jerked a little, the urge to move towards her palpable, his need to comfort instinctive. But he didn't. He stayed seated by the desk, giving her space, asking her if it was a robbery and letting her continue like it wasn't so painful, and she appreciated it as she blinked back the tears attempting to congregate in the corners of her eyes.

"The killer was never caught," she finished, staring down at her hands.

"Why do you wear the watch?" he asked softly, and she took a deep breath before diving into another sea of gut wrenching memory.

"My dad took her death hard. He's sober now," she said with her lips momentarily quirking upwards in a sad, but proud smile. "Five years."

He tried to offer her a smile back, but it was forced and weak and heartbroken, which she imagined matched hers pretty well.

"So, this is for the life that I saved," She raised her wrist, touched her index finger to the leather band of the watch. "And this," she continued, forcing the lump rising in her throat to recede as she retrieved the chain from under her shirt. "is for the life that I lost." she finished on a sigh, closing her fingers around her mother's wedding band and letting her eyes rest on the shimmering stone.

The silence that followed was stifling and she tried to joke, to lighten the torturously dark mood that had fallen over them because of her.

"So I guess your Nikki Heat has a backstory now, Castle."

But her attempt at levity fell flat and when she looked up at him, she could immediately read the grief written all over his face. The pain of her loss, her hardships, taking root inside of him as well, and she shook her head as if to dismiss it. She didn't want that. This was not why she came here, not at all.

"Beckett." His response of simply her name was too solemn for her liking and too much, it was all too much, and how could she have been so stupid as to bring this up?

"I think I'm going to go," she mumbled, pointlessly tugging the lapels of her coat together and making her way towards the door. "See you-"

She stuttered to a stop at the gentle closing of his hand around her forearm.

"Kate-"

"_What?_" she snapped a little too harshly.

"I'm sorry," he murmured rising from his seat to stand beside her, and the sincerity burning in his gaze made her bruised heart swell and ache against her chest. She needed him to stop looking at her like that. "I know it's not enough – not nearly enough – but I'm so sorry."

She bit down hard on her lip - she refused to actually cry in front of him - and flicked her eyes down to the hand still clamped around her arm. He released it immediately, but she didn't move away.

She wasn't as familiar with this Castle - the one who spent his evenings playing laser tag with his daughter and stared at her with overwhelming concern and compassion pouring from his glistening eyes. She only knew the playboy she had seen portrayed in the press, and the man-child she dealt with at work. The Castle she had shared her story with tonight, the man standing next to her, was currently neither of those things. This Castle was closer to the kind of person she had imagined while curled up alone in her bed with his book in her arms and the pain of loss in her heart.

She could grow to like this Castle. If she was being honest, she knew she already did.

Almost experimentally, Kate lifted one hand to his face, slowly skimmed her fingers through the light valley of scruff peppering his jaw, and watched him stiffen in response.

She might not know the real Castle as well as she would have thought, but he also didn't know the real her. Not the version she kept hidden anyway. She found herself wanting to know more, to learn more about him, and perhaps allow him a few more pieces of herself in return. With time, maybe they could both be taught.

"Beckett?" he questioned, voice close to a whisper, eyes wide and searching her face as her thumb swept over his bottom lip.

"Kate," she murmured absentmindedly, stepping closer. "It's Kate."

Her eyes skated down the line of his throat as he swallowed thickly. She was making him nervous and it almost made her laugh, because never would she have thought Richard Castle would be looking at her with a mixture of fear and something between lust and longing while she stood before him with intent in each movement she made.

Before he could back away, she used the hand on his jaw as leverage to pull his hesitant body to hers, and then she kissed him.


	2. Chapter 2

It was more delicate than she would have expected their first kiss to be. His lips were tentative, careful and barely there as they cautiously caressed hers, and it was sweet and pleasant, but she definitely wanted more.

Kate's hands moved to his chest while she nibbled on the soft flesh of his lower lip with her teeth, fisting in his shirt and slowly feeling whatever control he'd managed to harbor slipping away as his tongue slid into her mouth and his palms settled on her waist.

She easily walked him backwards until they both collapsed into the armchair he'd occupied only moments before, his grip on her hips pulling her into a straddle over his lap, and she felt more than heard the low moan that reverberated from his chest at the pressure of her body so perfectly aligned with his.

Her coat was thrown onto the desk, her soft grey cardigan followed, but he took his time unbuttoning her shirt, detaching his lips from hers to trail them down the exposed expanse of porcelain skin he revealed with the removal of each button. Her hips bucked when his mouth closed over her nipple through her bra, his tongue laving over the rough lace until she was nearly crying out from the rush of combined sensation.

"Beckett. Kate." he panted, lifting his head and running his hand through her hair, cradling the back of her skull. "I want you-"

She ground down against the hard evidence of his want, watched him jerk underneath her, and grinned. "I know."

He threw his head back and swallowed, and she couldn't help leaning forward to press her lips to the delicious column of his throat, letting her tongue sneak out to taste the salty sheen of sweat covering his skin.

"We can't do this in here," he gasped, fingers digging into her thighs, sliding underneath until he had a firm hold on her. "The walls are made of books."

Castle pushed off from the chair with her body wrapped around him and she clenched her thighs instinctively when he momentarily wobbled before finding his footing and making it to his bedroom in three, quick strides. He kicked the door shut behind them and then spun around, pinning her to the hardwood.

Her head fell back against the door with a thud as his mouth immediately resumed its assault her neck, sweeping his tongue over her thundering pulse and nipping his way down to the hard ridge of her collarbone.

"Castle," She undulated her lower half into his. "Bed. Take me to bed."

He wordlessly complied, skimming his lips along the line of her jaw before gently laying her down atop the comforter. Kate pulled him down with her and locked her legs around his waist, desperate to keep their physical connection as Castle continued to work at her dress shirt. Fumbling his fingers across her chest, he finally managed to undo the last few buttons, looking down hungrily at his cleared effort while she freed her arms from the blouse and tossed it over the edge of the mattress.

"Fuck," she gasped when his mouth was on her again, reclaiming her breast with his mouth, not bothering to rid her of her bra, as if he knew how much the rough scratch of the lace over her skin drove her crazy.

She mewled in frustration, surging her body upwards so she could reach behind and undo the clasp. He helped her untangle the straps from her arms and flung the lingerie across the room, but when he returned his attention to her body, he spent a second too long staring down at her and she caught something unfamiliar blossoming in his eyes. Something she wasn't near ready to see.  
"Castle-"

"You're gorgeous, Beckett." And then he was lowering his head and swirling his tongue over her nipple once more, tweaking the other with dexterous fingers, and she couldn't remember what she had planned to say.

Her head thumped back into the pillow and her jaw fell open in a silent moan as he started to drift downwards, licking a path from her chest to her stomach, her taut muscles twitching and contracting uncontrollably at the onslaught of tongue and teeth scraping over the hot, fevered planes of her skin.

He rid her of her pants with ease, the black slacks slipping off effortlessly and fluttering to the ground at the foot of the bed. He brushed his lips over the sharp jut of her hipbone and flicked his dark eyes up to her for confirmation before he removed the sodden red lace of her underwear as well.

She was suddenly glad it had been laundry day at her place.

"_Castle_," she gasped, her voice sounding so desperate and foreign to her ears as the sudden scorching heat of his mouth covered her, sending her body arching off the bed and her hand automatically diving into his hair.

She tried not to pierce his scalp with her nails, using her unoccupied hand to grip the sheets instead as the tip of his tongue slid through her wetness. His fingers joined only moments later, teasing at her entrance while his mouth sucked lightly on her clit and her vision grew blurry.

"Castle, Castle, please-"

His fingers glided inside and curled, and – _oh god, oh god, right there _– he had to pin her hips down with his other hand to keep her from jerking so wildly against his mouth.

It wasn't long at all before she was nearly sobbing, writhing helplessly under his wicked mouth, and it was ridiculous and embarrassing and god, she _hated _him.

He hummed as his tongue worked her clit, like he was pleased with himself, and she wanted to lift her leg and dig her heel into his back, punish him for it, but the vibrations had a string of strangled curses streaming past her lips instead.

It only took a couple more thrusts and twists of his fingers along with the flat press of his tongue against her to have her shattering under his mouth.

He only gave her seconds to come down, dropping twin kisses to her inner thighs as she panted through the tremors still racing through her limbs like bolts of electricity. But then his devastatingly talented mouth was traveling north, up the expanse of overly sensitized skin to her lips, where his mouth fused against hers. She sucked on his tongue, tasting remnants of herself still lingering on his taste buds, and snaked an arm around his neck, scratching impatiently at the soft cotton of his shirt.

"You have too many clothes," she rasped, noticing he was still fully dressed and she was completely naked.

With the hand that wasn't buried in his hair, she grasped for his belt, getting the buckle undone in a matter of seconds and sliding it free from his jeans. Castle's head dropped to her shoulder when she pulled his zipper down, purposely applying pressure as the teeth separated and causing him to swear into her skin.

Kate slipped her hand past the waistband of his boxers, immediately stroking her fingers up and down the hot, throbbing length of him. She squeezed and he grunted, dragged his teeth over the juncture between her shoulder and her neck.

She shuddered, circled his tip with her thumb. "Stop, Kate – won't last."

Beckett unhurriedly drew her hand away and returned to the task of removing his clothes, started by tugging the hem of his shirt up his body until he had to lift to his knees to shuck it off himself.

The fit build to his body impressed her. His form had been displayed quite well through his expensive button downs and well fitting slacks at the precinct, but she hadn't imagined he would be this toned. She smoothed her palms over his broad chest, raked her nails down his firm stomach, watching his eyes flutter closed at her touch, and guided him back down to crush their bare chests together, the skin to skin contact making her hum with pleasure.

Her feet assisted in shoving his pants down his legs, and then finally, Castle was naked. But as he moved to position himself at her entrance, she rose onto her elbows, twined their legs together, and flipped them.

She smirked at the expression of shock and awe on his face as she settled over his lap in a straddle and reclaimed his erection in her hand, dragging his tip through her own arousal until he was groaning her name.

"Should've known you'd want to be on top. Since you prefer to be in control and all." he managed to say through gritted teeth and she rolled her eyes.

"Mmm, not the time for character analysis', Castle."

Kate placed her hands on his abdomen to steady her trembling body and bit her lip to silence the sounds dying to burst from her throat as she sank down onto him slowly, inch by inch, until he was filling her completely. They both took a moment to adjust; he was big and – and it had been a while for her, but then she rocked her hips, and let a breathy sigh escape, because _fuck,_ he felt amazing.

"Here," he murmured tightly, reaching for her hands and she laced their fingers together, using his grip for support as she continued to roll her body into his, riding him at a leisurely pace at first before allowing herself to go faster as the spring of arousal low in her stomach coiled tighter.

His hips lifted to accommodate her movements, a raw whimper tumbled past her lips, and she had the urge to lean forward, find his mouth for a searing kiss. Castle levered himself up before she could reach him though and the change in angle, the way he drove deeper into her, had her _so _close, sensation like fire rushing through her bloodstream.

"Oh, God," she gasped into his open mouth, riding his lap harder, picking up speed and gripping his biceps so roughly she had a feeling she would leave crescent shaped marks on his skin. "Castle, I can't-"

"I got you, Kate. Let go." he grunted into her hair, his palms pressing flat against her rigid spine and sending a sharp arrow of heat through her middle.

She buried her face in the crook of his neck to muffle the ragged cries as she came, stars bursting behind her eyelids and the white hot flood of release stealing her breath, but she kept her hips rocking against his until he spilled inside her a second later.

Castle slumped backwards onto the mattress and she went with him, unable to move even if she'd wanted to.

Her eyelids started to droop within seconds of lying over his body, letting the cooling air of his bedroom dry the film of sweat covering their skins and the steadying beat of his heart under her ear lull her towards unconsciousness.

Slight panic began to flutter in her chest though, ominous regret whirling alongside it, and she curled almost instinctively to avoid them, to shield herself from their unwanted existence. Castle took her movement as a sign of discomfort and carefully turned on his side, effectively easing himself out of her.

She shot him a timid lift of her lips and exhaled heavily, rolling onto her back to stare at the ceiling. She knew she should probably regret what she had just done with Castle, remind herself how it would change everything between them, that he would most likely hurt her, break her heart at some point - but she couldn't. She didn't.

The threats of panic and regret disappeared, and Beckett felt at peace.

"Falling asleep?" he asked quietly, his voice soft and low as he watched her with caution from his place a few inches away.

"Mm, yeah." she yawned, closing her eyes to blink and forgetting to open them again.

* * *

**_One more chapter..._**


	3. Chapter 3

The first time he had ever fantasized about her had been after she'd crashed his reading at the bookstore a couple of weeks ago in that damn pink dress that was too short and too revealing in how it draped over the creamy silk of her skin. It was the first time he had been overcome with the constricting need to rip her clothes off.

The sight of her body – her _legs _– so svelte and on display, and the intentional look of lust burning like flames in her eyes when he spotted her in the crowd had been almost unbearable, causing his usually perfect storytelling voice to stutter in front of all those people.

He'd gotten off in the shower with her name on his lips later that night.

But fantasy was as far as he had ever assumed he would go when it came to the seduction of Kate Beckett. She had fascinated him from the first day – obviously he'd made that quite clear when he had decided to bulldoze his way into her life – and he was sure she had always been aware that he was attracted to her, but it was never…_real_. He had never fathomed anything real with her.

He had never imagined she would be lying next to him in bed, one long leg draped over his thigh, and her head practically sharing a pillow with his after making lo-

Sex, he corrected himself, they'd had sex. Too early for mentions of four letter words that started with L. He didn't even want to _think_ about that terrifying word.

Maybe in the near future though? If she didn't bolt out the door the moment she awoke from what appeared to be a blissful slumber.

No, he wouldn't have thought so before, but after tonight, after watching her open up to him about her past, despite how much it had visibly pained her, and learning her body like a map, tracing over every valley of skin and ridge of bone with his mouth, he believed he could love her. It scared the shit out of him, but it was possible.

Just not – not yet.

Castle sighed and squeezed his eyes shut. He needed to stop thinking.

Kate stirred slightly beside him, burrowing closer to the warmth of his body, erasing the inch of space he had strategically kept between them once she had fallen asleep. Not that he was terribly disappointed to have her lithe figure pressed up against him again.

She huffed softly, releasing a cool breath of air over the skin of his throat, and damn, he really wanted to touch her, comb his fingers through the short spikes of her hair and memorize the stunning contours of her face while the opportunity was there.

She was so close. All he would have to do is lift his arm and he could brush his fingers down the slash of her cheekbone. But then he would risk waking her, and then she might leave.

"Stop staring at me," she muttered, one of her eyes cracking open to glare at him. "I told you, it's creepy."

He startled at the rasp of her voice, not expecting her to swim into consciousness yet, and his movement seemed to set off a ripple effect, because suddenly her body was stiffening and the pang of disappointment was real this time as she gently slid her leg from his, retracted her entire body from his, and turned onto her back.

He felt stupidly cold at the loss.

"Beckett-"

_Kate. _She'd told him to call her Kate.

"Kate."

Her sharpened hazel eyes flitted over to him and he swallowed, unsure what exactly he had planned to say.

"Are you leaving?" he blurted and internally cursed himself.

Smooth, Rick.

She furrowed her brow and propped herself up on her elbows.

"Did you want me to?"

"No!" he said immediately, her creased eyebrows rising upwards now. "I just meant – I thought you wouldn't want to stick around." he shrugged.

The corner of her mouth quirked upwards.

"Thought I was going to use you for your body and go?" she smirked and he found himself chuckling.

"Feel free to use my body anytime you like, Detective."

Her lips curled into a devious grin and she glanced to his alarm clock.

"I've still got an hour before I should probably head to my apartment, if you can handle another round…"

Castle's heart stuttered but his body didn't miss a beat, reacting to her words instantly.

* * *

She left over an hour later, just before the sun could rise on the horizon, missing the lace bra he knew for a fact was under his bed because that was where he had kicked it on his way back from the bathroom earlier in the night.

He had shown up at the precinct the same as he always did, cracked the Cavanaugh case with her, brought a family justice, all while trying not to gaze so obviously at her every chance he got.

He knew he failed each time she shot him a heated, but reprimanding glare.

But sitting next to Kate Beckett at work after he knew what she looked like underneath those professional blouses and dress pants was an incredibly difficult feat. Could she really blame him?

Later that evening, after she'd finished up her paperwork and they'd shared a brief talk at her desk about Alexis along with a joke over the lack of substance to his novels, she gathered her coat and prepared to leave.

"Until tomorrow, Detective."

She glanced down at the floor with a small smile tugging at her lips.

"You can't just say night?"

"I'm a writer, night is boring. Until tomorrow is more…hopeful."

She nodded. "Yeah well, I'm a cop. Night."

He watched her walk away from him, out of the bullpen and into the elevator, and once the doors to the lift slid closed, he bolted out of his seat.

Esposito shot him a bewildered glare as he hurried past him and towards the stairs, galloping down the steps in record time. He reached the lobby just as she was exiting and he slowed to a trot as he bounded after her. He didn't try to gain her attention until they were both a good distance from the Twelfth.

"Kate,"

She glanced over her shoulder, an almost expectant shimmer in her eye, and grinned when he was standing in front of her.

"Yeah, Castle?"

He grabbed her by the lapels of her coat and slanted his lips over hers, kissed her until a soft whimper was escaping her mouth and her fingers were clawing at his waist, and then he pulled away.

He smiled at the startled look on her face and let her go. "Night."

"Castle," she hissed, catching him by the hand as he attempted to turn back to the precinct. "I changed my mind," she smirked, tentative but sure as she twined their fingers. "Night's only beginning."

* * *

**_A/N: I apologize to those who found this story unrealistic due to the time it is set in. But I personally love season 1 and wanted to explore the possibilities of this scenario and tried to do so as realistically and in character as I could. _**

_**Thank you to any and all who took the time to read, review, follow, and favorite. Feedback is always sincerely appreciated.**_

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